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EnergySails harness wind and solar power to cut ship fuel consumption


November 13, 2012

The Aquarius Eco Ship concept based on the EnergySail technology that uses solar panels embedded in rigid sails

The Aquarius Eco Ship concept based on the EnergySail technology that uses solar panels embedded in rigid sails

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In the 400 years or so leading up to the adoption of steam power in the 19th century, sailing ships ruled the waves. In an effort to cut increasing fuel costs and reduce emissions, sails are set to once again prove their worth. But unlike the sails proposed by B9 Shipping and the Wind Challenger Project, Japan-based Eco Marine Power (EMP) is developing sails with an even more modern twist. Rather than just harnessing the power of the wind, EMP’s EnergySail can be fitted with solar panels to also harness solar power.

The EnergySail is a rigid take on the sail that sits upon a pole and automatically rotates to take full advantage of the wind and help propel the vessel. At the same time, solar panels embedded in the sail harness energy from the sun to provide electrical power to reduce the amount of fuel used by auxiliary generators. In bad weather or when the ship is at anchor, the sails can be lowered and stored.

However, the solar panels can also be used while the ship is in port, with energy stored in battery modules, providing the potential for totally emissions-free operation while not at sea. EMP says a modified version of the EnergySail could also be used to collect solar energy when lowered in the horizontal position. The company claims the rigid sails have been designed to require little maintenance and to withstand the high winds found at sea.

Building on its previous Aquarius Eco Ship concept – a cargo ship design boasting an array of 14 rigid sails – EMP has recently unveiled a modified version of the system aimed at vessels like naval frigates, which would use four sails, and smaller patrol vessels and coast guard ships that might be fitted with just two. Single EnergySails could also be fitted as standalone units on even smaller vessels, such as cable laying vessel or oceanographic ship, while a variation of the EnergySail targeted at even smaller ships, such as ferries or fishing vessels, is also in development.

EMP estimates that, depending on the number, size, shape and configuration of the EnergySails, a fossil fuel-powered ship’s annual fuel consumption could be cut by up to 20 percent, while vessels powered by an electrical propulsion system could cut fuel consumption by around 40 percent. In addition to the fuel consumption and noxious gas emission benefits, EMP says EnergySails could also allow ships to operate more quietly at lower speeds in bays and harbors in comparison to conventional ships.

Currently testing a control system that will automatically raise, lower and position each EnergySail based on the prevailing weather conditions, EMP is hoping to begin sea trials in 2013.

Source: Eco Marine Power

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

The greater the weight of cargo, the greater the weight of pressure on it's air bladder to produce power to super charge it's own propulsion.

Flipider Comm

Having solar panels that stick up like that is going to add tremendously to the ships wind resistance which will require additional energy to overcome. Which do you decide to do maximize wind power or maximize solar power.

I am all for using sails to propel ships. I dream of sailing a 100ft windjammer trading amongst the south pacific isles and using sails to propelled an anti-submarine warfare vessel will deny blade count speed estimates to the enemy. I am convinced that this project is designed to shut up environmentalists not produce a practical ship.


Would it not be better to place the solar panels on the hull eliminating any resistance?

Nolley Martis

There's a reason 19th century windjammers had from three to five masts around 150 feet high, each of which carried several sails, giving a total area several orders of magnitude greater than those shown in the illustrations above.

That was on hulls smaller and lighter than the illustrated freighter too.

Just put 'windjammer' into any search engine and look at the pictures, compare the area of the sails to the size of the rest of the vessel.

As for the solar panels, it is unlikely that the orientation for electrical efficiency and the alignment for best wind thrust will be aligned most of the time.

More unsubstantiated rubbish purely designed to con funding out of some gullible organisation - probably funded by the taxpayer, of course.


Wouldn't kites be much better for this sort of deal? Why not bleed excess wind energy off to a generator and ditch the solar sails for ship mounted panels or coatings once the price is reasonable?

Alan Belardinelli

Aquarius MRE website - the bit left off the bottom of the article allowing Catweazle/Pikeman to vent spleens :

"Land-based testing of the system is scheduled to finish in early 2013 and Eco Marine Power is currently discussing with several companies plans for installing a system onboard a ship for sea trails during the second half of 2013."

I.e. the company is not asking for massive funding for vapourware, Aquarius is only in lab development and will prototype. Early days folks, too early to be critical over something that does not exist yet.


Thorium LFTR styled reactors from China will most definitely have marine applications, and will most decidedly change the face of the energy maps of the world. (See: (See:

Bruce Miller

This is a very lame implementation of a reasonable idea. Look at any proper sailing vessel. It has mast heights that are at least as long as the vessel. These cute little billboards plastered on the deck of the tanker are a non-solution to the problem of ship energy use. It is doubtful that a measurable difference in speed or fuel consumption would be realized. See: for an example of proper proportions.

The combining of PV and sail power is fine, but locating PV on the sails is a bad idea, as the proper trim of the sails will likely not be the right direction for PV. Tankers have lots of deck area, so mount the PV as it is done on a flat roof.

There is far more to be gained in shipboard energy reduction by simply slowing down. Even more beneficial would be to shape the hull in a way to reduce resistance instead of the boxy shape typical of large tankers.

The only value in EMP's approach would be as a weak form of greenwashing - in other words, it's of no use at all.


Saw something similar on Trendhunter some years back. Love the idea for cruise & cargo ships alone & some yachts.

Stephen Russell

Interesting to see which it would favor, high wind little sun, position sales with wind, high sun, no wind, position sails toward sun. I was having a discussion with a captain who said even though hybrid systems on boats are a long way off, additional solar energy for battery systems would be great. If only electric motors were as powerful as the huge hydraulic systems these boats require.

Nicolas Zart

Odd thought for the critics, the illustration is displaying the solar panels at angles they would have at 6 - 10 am and 2 - 6 pm ( 0 & 180 Degrees) panels rotate vertically to follow the sun so for 1/3rd of the day have little surface area.

If the wind is behind the direction of sail it adds to ship speed, if a breeze comes from Port or Starboard it acts on top hamper, tilting the vessel slightly, since the panels are rotating the overall effect is neither to give or take speed from the vessel. Only if there is a headwind will there be a significant force acting against the direction of sail. The odds are then in a headwind the panels would be furled.

Recap in a voyage there is a 25% chance of a headwind, during which in the early morning and late afternoon solar panels would be lowered out of harms way, strong winds mean no panels deployed. Winds behind the stern are beneficial so panels are always deployed.


re; Nicolas Zart

The only advantage hydraulic reduction has over electrical reduction in ship's propulsion is that hydraulic reduction costs less to build do to the cost of copper.

For ultimate efficiency having a engine that runs at maximum efficiency at the same RPM as the screw does at cruising speed.


They would do better to use each system separately. The square area of the horizontal surfaces, of each ship exceed the area of the sails by a wide margin. Use sails as sail, and solar panels everywhere they will fit without interfering with the operation of the ship. It is highly unlikely that the wind and the sun would align for the best use of each. Even the exposed hull could be used as a solar collector with the added advantage of reflected light off the sea. In addition, the engine heat and the sea water cooling could generate power below the waterline with thermopiles.


Okay a few basics here:

The rigid sails are meant to reduce fuel consumption, not be the primary source of propulsion. It isn't a theory - it has been done before in the 1970's and 1980's.

The rigid sails move and are computer controlled. Obviously they will not be left in a position where they simply creates drag.

If you look at any "proper" sailing vessel you will notice they tend to have keels and are not large ocean going tankers or bulk ore carriers. In other words the system is designed to be used on modern powered vessels - not turn ships into yachts.

The Aquarius MRE System includes energy storage modules.

P.S There is an FAQ available

Greg Atkinson

re; Greg Atkinson

Sailing ships are not automatically yachts. The largest pure sailing ships ever built were used to haul ore, coal, and oil. In fact the only seven mast schooner ever built spilled her cargo of 58,000 barrels of light paraffin oil causing a tremendous oil spill on the Scilly Isles.


Wow! This is so cool! Solar and wind energy is really useful in cutting fuel consumption in big boats and ships. I guess, this would be a better strategy in lowering the fuel price in the middle east. Less demand of fuel, price gets low. Thanks!

Daisy Liddell

In a sixty foot sea those wee masts would not survive, whatever happened to common sense?

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